| Project ID. / 計畫代碼 | NCREE-R2005001 |
| 主持人 | 翁作新 |
| PI | Tzou-Shin Ueng |
| 單位 | 國震中心 |
| Organization | NCREE |
| 計畫名稱 | 振動台大型砂土試體受震反應與液化之探討 |
| Project Name | Seismic responses and liquefaction of a large sand specimen on shaking table |
| Project No. / 計畫編號 | |
| Keywords / 關鍵字 | soil liquefaction, shaking table test, shear box |
| Begin Date / 計畫啟始 | 2005/1/1 |
| End Date / 計畫結束 | 2005/12/31 |
| Abstract / 摘要 | 台灣地處於地震帶上，由於地震引致砂土之超額孔隙水壓激發，而產生液化破壞而可能引起土層大量的變形，往往造成重大災害。為了了解此一現象發生之行為，必須對土壤因受地震引起之孔隙水壓激發特性予以研究。同時土壤受震時，地表下孔隙水壓會有變化，此對土壤與結構互制行為會有相當之影響，根據現有文獻資料顯示，即使超額孔隙水壓不大，但地盤勁度已具某種程度之軟化，進而影響上部結構之振動反應及其安全。然而現行設計中，對此地盤軟化行為之考量，尚未有合理可行之方法，因此必須對土壤液化及其過程中土壤與結構互制關係之行為加以深入的研究。配合國家地震工程研究中心之大型振動台，本中心已於88年製作完成大型液化模型剪力盒、砂土試體霣落器以及相關的周邊設備，且於89-90年間陸續完成空箱測試、橡皮膜黏貼、裝水試驗以及試體準備演練，並在91年進行試體準備結果之驗證以及第一次振動台土壤試體液化試驗，成果豐碩。本年度之計劃將延續進行不同參數絛件下之振動台液化試驗，並針對一維及二維運動模式的不同，探討其對液化現象所產生影響之差異。根據振動台試驗成果，可了解現地土壤液化機制以及地盤受震土壤中振動傳遞現象，並可建立大型物理模型試驗與傳統室內元素試驗之抗液化強度間之關係，經由適常之修正，可使傳統元素試驗之液化潛能評估結果更具工程應用價值。 |
| Abstract | Earthquake shaking induces pore water pressure generation that in turn can cause soil liquefaction. Soil liquefaction and associated structural damage during strong earthquakes are serious problems causing losses of lives and properties. Cities located at soft alluvial deposits and the undergoing hydraulically reclaimed lands for industrial parks are both susceptible to soil liquefaction. Thus, it is necessary to study the liquefaction problem including soil-structure interaction in these areas and their remedial measures. A large-scale biaxial shear box was thus developed and designed to be used on the shaking table at NCREE that a large soil specimen can be tested under one- and two-dimensional earthquake shakings. The manufacture, testing, and instrumentation of the shear box and evaluation of sample preparation using the wet sedimentation method have been completed. The first liquefaction test on Vietnam sand using the large shear box on the shaking table at NCREE was conducted in 2002. This year we continue to perform liquefaction tests using the large shear box on the shaking table. From the test results, we can better understand the liquefaction mechanism, ground shaking responses through soil, and explore the technical ability for large-scale model tests. Moreover, these data are valuable for establishing liquefaction evaluation criteria and improving seismic design and disaster prevention concerning soil liquefaction. |